range-diff: split lines manually

Currently range-diff uses the 'strbuf_getline()' function for doing
its line by line processing.  In a future patch we want to do parts of
that parsing using the 'parse_git_diff_header()' function.  That
function does its own line by line reading of the input, and doesn't
use strbufs.  This doesn't match with how we do the line-by-line
processing in range-diff currently.

Switch range-diff to do our own line by line parsing, so we can re-use
the 'parse_git_diff_header()' function later.

Signed-off-by: Thomas Gummerer <t.gummerer@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/range-diff.c b/range-diff.c
index 9242b8975f49ac87a647d453b7cc044a4deb7889..784fac301bb6cc432d7e7fb69de066125c6aa594 100644 (file)
--- a/range-diff.c
+++ b/range-diff.c
@@ -24,6 +24,17 @@ struct patch_util {
        struct object_id oid;
 };
 
+static size_t find_end_of_line(char *buffer, unsigned long size)
+{
+       char *eol = memchr(buffer, '\n', size);
+
+       if (!eol)
+               return size;
+
+       *eol = '\0';
+       return eol + 1 - buffer;
+}
+
 /*
  * Reads the patches into a string list, with the `util` field being populated
  * as struct object_id (will need to be free()d).
@@ -31,10 +42,12 @@ struct patch_util {
 static int read_patches(const char *range, struct string_list *list)
 {
        struct child_process cp = CHILD_PROCESS_INIT;
-       FILE *in;
-       struct strbuf buf = STRBUF_INIT, line = STRBUF_INIT;
+       struct strbuf buf = STRBUF_INIT, contents = STRBUF_INIT;
        struct patch_util *util = NULL;
        int in_header = 1;
+       char *line;
+       int offset, len;
+       size_t size;
 
        argv_array_pushl(&cp.args, "log", "--no-color", "-p", "--no-merges",
                        "--reverse", "--date-order", "--decorate=no",
@@ -54,17 +67,20 @@ static int read_patches(const char *range, struct string_list *list)
 
        if (start_command(&cp))
                return error_errno(_("could not start `log`"));
-       in = fdopen(cp.out, "r");
-       if (!in) {
+       if (strbuf_read(&contents, cp.out, 0) < 0) {
                error_errno(_("could not read `log` output"));
                finish_command(&cp);
                return -1;
        }
 
-       while (strbuf_getline(&line, in) != EOF) {
+       line = contents.buf;
+       size = contents.len;
+       for (offset = 0; size > 0; offset += len, size -= len, line += len) {
                const char *p;
 
-               if (skip_prefix(line.buf, "commit ", &p)) {
+               len = find_end_of_line(line, size);
+               line[len - 1] = '\0';
+               if (skip_prefix(line, "commit ", &p)) {
                        if (util) {
                                string_list_append(list, buf.buf)->util = util;
                                strbuf_reset(&buf);
@@ -75,8 +91,7 @@ static int read_patches(const char *range, struct string_list *list)
                                free(util);
                                string_list_clear(list, 1);
                                strbuf_release(&buf);
-                               strbuf_release(&line);
-                               fclose(in);
+                               strbuf_release(&contents);
                                finish_command(&cp);
                                return -1;
                        }
@@ -85,26 +100,28 @@ static int read_patches(const char *range, struct string_list *list)
                        continue;
                }
 
-               if (starts_with(line.buf, "diff --git")) {
+               if (starts_with(line, "diff --git")) {
                        in_header = 0;
                        strbuf_addch(&buf, '\n');
                        if (!util->diff_offset)
                                util->diff_offset = buf.len;
                        strbuf_addch(&buf, ' ');
-                       strbuf_addbuf(&buf, &line);
+                       strbuf_addstr(&buf, line);
                } else if (in_header) {
-                       if (starts_with(line.buf, "Author: ")) {
-                               strbuf_addbuf(&buf, &line);
+                       if (starts_with(line, "Author: ")) {
+                               strbuf_addstr(&buf, line);
                                strbuf_addstr(&buf, "\n\n");
-                       } else if (starts_with(line.buf, "    ")) {
-                               strbuf_rtrim(&line);
-                               strbuf_addbuf(&buf, &line);
+                       } else if (starts_with(line, "    ")) {
+                               p = line + len - 2;
+                               while (isspace(*p) && p >= line)
+                                       p--;
+                               strbuf_add(&buf, line, p - line + 1);
                                strbuf_addch(&buf, '\n');
                        }
                        continue;
-               } else if (starts_with(line.buf, "@@ "))
+               } else if (starts_with(line, "@@ "))
                        strbuf_addstr(&buf, "@@");
-               else if (!line.buf[0] || starts_with(line.buf, "index "))
+               else if (!line[0] || starts_with(line, "index "))
                        /*
                         * A completely blank (not ' \n', which is context)
                         * line is not valid in a diff.  We skip it
@@ -117,25 +134,24 @@ static int read_patches(const char *range, struct string_list *list)
                         * we are not interested.
                         */
                        continue;
-               else if (line.buf[0] == '>') {
+               else if (line[0] == '>') {
                        strbuf_addch(&buf, '+');
-                       strbuf_add(&buf, line.buf + 1, line.len - 1);
-               } else if (line.buf[0] == '<') {
+                       strbuf_addstr(&buf, line + 1);
+               } else if (line[0] == '<') {
                        strbuf_addch(&buf, '-');
-                       strbuf_add(&buf, line.buf + 1, line.len - 1);
-               } else if (line.buf[0] == '#') {
+                       strbuf_addstr(&buf, line + 1);
+               } else if (line[0] == '#') {
                        strbuf_addch(&buf, ' ');
-                       strbuf_add(&buf, line.buf + 1, line.len - 1);
+                       strbuf_addstr(&buf, line + 1);
                } else {
                        strbuf_addch(&buf, ' ');
-                       strbuf_addbuf(&buf, &line);
+                       strbuf_addstr(&buf, line);
                }
 
                strbuf_addch(&buf, '\n');
                util->diffsize++;
        }
-       fclose(in);
-       strbuf_release(&line);
+       strbuf_release(&contents);
 
        if (util)
                string_list_append(list, buf.buf)->util = util;